The Video Electronics Standards Association (VESA) DisplayPort standard defines a system and apparatus capable of transporting video, audio and other data between a source device and a sink device over a communications interface. The DisplayPort standard addresses internal connections such as interfaces within a personal computer or monitor. In addition, the DisplayPort standard addresses external display connections, including interfaces between a personal computer and a monitor or projector, between a personal computer and a television, or between a device such as a digital versatile disk player and a television.
When a physical connection is established between a DisplayPort source device and a DisplayPort sink device, link training is performed through a handshake in an attempt to establish the bandwidth and electrical parameters of the transmission channel, including number of lanes, transmission rate, drive current and equalization level. The source device performs link training to configure a link based on a number of factors, including the sink device capabilities and source device capabilities.